Export a keyframed animation made in Blender to Three.js (no bones involved)
See threejs docs: https://threejs.org/docs/#manual/en/introduction/Loading-3D-models. I'd recommend trying the Blender glTF exporter suggested there, glTF-Blender-Exporter. It does support keyframed animation.

Once you've exported something, usage is:

var loader = new THREE.GLTFLoader();
loader.load('my-model.glb', function (gltf) {
  var model = gltf.scene;
  var mixer = new THREE.AnimationMixer(model);
  var clip1 = gltf.animations[0];
  var action1 = mixer.clipAction(clip1);
  action1.play();
});

// ... in render loop
var dt = clock.getDelta()
mixer.update(dt);


You can also test your model in three.js without writing code, with http://gltf-viewer.donmccurdy.com/.